18 Physical Destination Property Reference

Physical Destination Properties

Table 18-1 lists the configuration properties for physical destinations. These properties can be set when creating or updating a physical destination. For auto-created destinations, you set default values in the broker's instance configuration file (see Table 17-3).

Note: When flow control is in effect (limitBehavior = FLOW_CONTROL), it is possible for the specified message limit to be exceeded because the broker cannot react quickly enough to stop the flow of incoming messages. In such cases, the value specified for maxNumMsgs serves as merely a hint for the broker rather than a strictly enforced limit. However, if the number of unconsumed messages would exceed imq.system.max_count, the broker generates a ResourceAllocationException indicating that the destination is full and rejecting new messages.

maxBytesPerMsg

String

-1

Maximum size, in bytes, of any single message

Rejection of a persistent message is reported to the producing client with an exception; no notification is sent for nonpersistent messages.

The value may be expressed in bytes, kilobytes, or megabytes, using the following suffixes:

b: Bytes

k: Kilobytes (1024 bytes)

m: Megabytes (1024 × 1024 = 1,048,576 bytes)

An unsuffixed value is expressed in bytes; a value of -1 denotes an unlimited message size.

REMOVE_LOW_PRIORITY: Throw out lowest-priority messages according to age; no notification to producing client

REJECT_NEWEST: Reject newest messages; notify producing client with an exception only if message is persistent

When FLOW_CONTROL is specified, it is still possible for the number of messages to exceed imq.system.max_count. In this situation, the broker generates a ResourceAllocationException indicating that the destination is full and rejecting new messages.

If the value is REMOVE_OLDEST or REMOVE_LOW_PRIORITY and the useDMQ property is true, excess messages are moved to the dead message queue. For the dead message queue itself, the default limit behavior is REMOVE_OLDEST and cannot be set to FLOW_CONTROL.

Maximum number of active message consumers in load-balanced delivery from queue destination

A value of -1 denotes an unlimited number of consumers.

This property used mostly in cases where message order is important and you want to provide backup consumers in case the principal consumer of a queue fails. If message order is not important, then you would simply use multiple consumers to provide for scalability and availability.

This property applies only to destinations in broker clusters, and cannot be changed once the destination has been created. If true, the destination is not replicated on other brokers and is limited to delivering messages only to local consumers (those connected to the broker on which the destination is created).

This property applies only to load-balanced queue delivery in broker clusters. If true, messages will be delivered to remote consumers only if there are no consumers on the local broker; the destination must not be restricted to local-only delivery (isLocalOnly must be false).

When XML validation is enabled, the Message Queue client runtime will attempt to validate an XML message against the specified XSDs (or against the DTD, if no XSD is specified) before sending it to the broker. If the specified schema cannot be located or the message cannot be validated, the message is not sent, and an exception is thrown. Client applications using this feature should use JRE 1.5 or above.

If set to false or not set, then XML schema validation is not enabled for the destination.

If set to true and XML validation fails, then the Message Queue client runtime will attempt to reload the XSD before attempting again to validate a message. The client runtime will throw an exception if the validation fails using the reloaded SXD.

If set to false or not set, then the schema is not reloaded if validation fails.

Footnote 1 In a cluster environment, applies to each individual instance of a destination rather than collectively to all instances in the cluster

Footnote 2 Does not apply to dead message queue

Footnote 3 Queue destinations only

Footnote 4 This property should be set when a destination is inactive: when it has no consumers or producers and when there are no messages in the destination. Otherwise the producer must reconnect.